The invention relates to an automatic adjusting device for a sighting system of an element which can be directed to a target, having an autocollimator consisting of a light source, a beam splitter and an objective, which images an illuminated area in autocollimation onto a position-sensitive detector.
EP-No. A2-0,254,101 discloses a device for the automatic adjustment of the sighting line of a sight for directing the tangent to the muzzle of an onboard cannon of an armored vehicle. The device exhibits a housing, in which an illumination unit, a splitter prism with a diaphragm, an objective and a quadrantal detector are fixedly disposed. The diaphragm, which is provided in the focal plane of the objective and is integrated in the splitter prism, is illuminated by means of the illumination unit. The objective forms an image of the illuminated diaphragm at infinity, which image is reflected by a reference mirror, which is erected firmly onto the on-board cannon and which represents the direction of the tangent to the muzzle, and is passed by the objective via the splitter prism to the quadrantal detector. In this way, angular deviations of the reference mirror can be detected and faulty adjustments can be appropriately compensated. In this known device, a partially-mirror-coated surface is required for the superposition of the adjusting (autocollimation) beam path and the target mark beam path (sighting beam path), whereby the transmission in both beam paths is reduced, which in turn requires the use of special light sources. In addition to this, as a result of the superposition of the adjusting beam path and the target mark beam, disturbances in the latter can occur.